


Duet

by actlikesummer



Series: The Kara Stark Chronicles [9]
Category: Marvel Cinematic Universe, Supergirl (TV 2015), The Avengers (Marvel Movies), The Flash (TV 2014)
Genre: Barry Allen & Kara Danvers Friendship, Barry Allen Needs a Hug, Crossover, Episode: s03e17 Duet, Kara Danvers Needs a Hug, Kara Danvers is Kara Stark, Natasha Romanov Is a Good Bro, Pietro Maximoff Lives, Protective Barry Allen, Protective Iris West, Protective Kara Danvers, Protective Natasha Romanov, Protective Siblings, Protective Steve Rogers, Protective Tony Stark
Language: English
Status: In-Progress
Published: 2021-03-01
Updated: 2021-03-08
Packaged: 2021-03-13 22:53:57
Rating: Teen And Up Audiences
Warnings: No Archive Warnings Apply
Chapters: 3
Words: 2,662
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/29783301
Author URL: https://archiveofourown.org/users/actlikesummer/pseuds/actlikesummer
Summary: After rendering both Kara and Barry unconscious, the Music Meister sends both them and their teams on missions that will prove that love really does solve everything.
Relationships: Avengers & Team Flash, Barry Allen & Kara Danvers, Barry Allen & Natasha Romanov, Barry Allen & Original Female Character(s), Barry Allen & Tony Stark, Barry Allen/Iris West, Kara Danvers & Tony Stark, Kara Danvers/Steve Rogers, Natasha Romanov & Original Female Character(s), Natasha Romanov & Team Flash, Steve Rogers & Iris West, Steve Rogers & Original Female Character(s), Steve Rogers & Team Flash, Tony Stark & Team Flash
Series: The Kara Stark Chronicles [9]
Series URL: https://archiveofourown.org/series/1557508
Comments: 5
Kudos: 17





	1. Intro

Kara’s vision cleared as her body swayed. Thankfully, she was sitting and figured Steve must have lowered her into a chair when she’d fainted. Then she heard someone calling her name.

“Kara?”

Blinking her eyes open, she saw that she was sitting on a stool in front of a well-lit vanity and panicked. Looking down at herself as someone started knocking at the door, she saw that her hair was curled and pinned up and found herself wearing black gloves and a black, sequined dress that looked as if it came straight from the 1920s.

“What the…”

The door swung open, interrupting her statement. “Kara?” The man ran over to her. “You’re on!”

Then he grabbed her hand and pulled her from the room.

“On what?”

As he dragged her down a flight of stairs past various performers, her head spun. She had no idea what was happening or where she was and felt extremely unsettled.

“Johnny canceled on us.” The man explained like it meant something to her. “You got the bump.”

“What…”

He smiled. “You’re the new opening act, kid!”

Then he pushed her through the curtains, and she was on a stage, face to face with a large crowd.

Letting out a wry chuckle, her heart rate sped up, and she looked around the room for a familiar face. When she found none, she could only think one thing.

“What the fuck did I get myself into now?”


	2. Heading to Earth-1

**Summary for the Chapter:**

> “By all accounts, he just…appeared from thin air, already inside the compound,” Vision told them.
> 
> “Is that even possible?” Wanda seemed shocked by this whole event.
> 
> “All of my statistical analyses say no,” the AI looked over at her. “and yet…”

Steve sighed as he stood over Kara’s unconscious body.

He’d caught her before she hit the ground—not that it would have hurt her—and brought her to the Med Bay immediately. Helen started to look her over right away but had yet to give them an update.

Looking out through the window of the exam room, the super-soldier observed the others.

As soon as the man had disappeared, he and Tony put Vision, Sam, and Natasha to work trying to locate him. They’d come back with no information, which had upset Tony worse than it did anyone else.

Rhodey, Tony, Wanda, and Pietro had followed them down to the Med Bay and had been waiting outside for updates ever since. Not long after they arrived, Layna joined them, having heard about the incident from Happy and FRIDAY.

She looked upset and scared for her mother.

Though they’d assured her that they would figure it out, she didn’t look convinced, and Steve didn’t blame her. Seeing someone so indestructible be taken out of the game was unnerving, and he knew they had to fix it soon.

When Helen nodded at him, he gestured for the whole group to join them for her updates. Layna hurried to her father’s side and looked up at him for support. Wrapping his arm around her, he faced Helen again.

“Well?” Steve wondered. “Do you know what’s wrong with her?”

The doctor shook her head. “I’m sorry, I don’t. I can’t find one thing wrong except that she’s unconscious, and her brain waves keep fluctuating.”

“Do we know why she fainted?” Tony asked her and Rhodey grunted.

“Yeah, and who the hell was that dude?” He asked angrily.

Sam shrugged. “We’ve run every search we could possibly do and still didn’t find any trace of him or even where he came from. We can’t even figure out how he got inside the building!”

“By all accounts, he just…appeared from thin air, already inside the compound,” Vision told them.

“Is that even possible?” Wanda seemed shocked by this whole event.

“All of my statistical analyses say no,” the AI looked over at her. “and yet…”

“So, what do we do?” Pietro wondered. “He is missing, and he says he is looking for the fastest man alive. If that’s not me, and it clearly isn’t, he was obviously lying.”

The room was silent for a second before Natasha looked between Steve and Tony. “You guys thinking what I am?”

The engineer nodded. “I mean, it makes sense.”

“Yeah, but why would he come here first if he just wanted to go there?” Steve questioned seriously, ignoring the confused looks of those around them.

“He needed one of the extrapolators.” Nat guessed. “I don’t keep mine on me, but I know Kara does. She’s been working on a way to possibly connect their phones to ours so she and Barry can communicate more.”

“But how would he even know about them or that you guys have them?” Tony frowned. “It’s not exactly common knowledge.”

“Speaking of common knowledge,” Sam cut in. “do you mind sharing with the class?”

Tony faced him. “A few years ago, we had a visitor from a different Earth. Yes, you heard me correctly; the multiverse exists. Anyway, this visitor was Barry, who is a superhero on his own earth. They call him the Flash because he is even faster than our own speedster. Sorry, pal, it’s just a fact.”

“Then, not too long after that, Barry came and asked for help fighting a group of aliens called the Dominators. Rhodey, you and Sam were both there when he and Cisco showed up in the tower, remember? Kara and I went and assisted them, so they had one of their techies build us some devices that allow us to pop over to their earth if we ever need to.” Nat continued. “That’s what he used to leave here, and my guess is that he’s gone over to Earth-1 in search of Barry.”

“Well, if he’s gone there to hurt your friend, what is stopping us from doing the same?” Wanda suggested. “If we can find this Barry before he does, maybe he will have the answers we don’t have right now.”

“That isn’t a bad idea.” Rhodey agreed. “But if you take her there and he finds you, you’ll need backup.”

“So I guess the only question is, who is earth jumping and who is staying here to defend this one?” Sam looked around at the group.

Steve stepped forward. “Obviously, I’m going with Kara. I’m sure Tony wants to go, too.”

“Definitely.”

“Same.” Nat raised her hand slightly. “I know the group and the location already, so I can help mediate.”

“Okay, it’s settled then. Tony, Nat, and I will-”

“I’m going too.”

Everyone turned to look at Layna, and Steve shook his head. “No way. You need to stay here where it’s safe.”

“No!” Her voice rose, and the soldier froze, not used to having her yell at him. “She is my mom, and I am not sending her there without going too. If anything happened and I wasn’t there, I’d never forgive myself. I’m going.”

The father and daughter stared at each other for only a moment—though it felt like longer to everyone in the room—before he sighed. “Fine. But you stay away from the fighting, and you do exactly what Auntie Nat, Uncle Tony, Uncle Barry, or I tell you to do. Understand?”

She nodded. “I promise.”

Ever the leader, he started again. “Okay, so as I was saying, myself, Tony, Nat, _and Layna_ will use the extrapolator and head over to Earth-1. From what Kara and Nat have told me, they have their own lab there that might be able to help bring her back to us.

“In the meantime, I want the rest of you to be on watch in case this mystery man shows up again. Natasha can leave you guys with her extrapolator on the chance you need to get to us for something, but I am hopeful that you guys will be able to handle yourselves. After all, you’ve been trained by the best and are now official Avengers.”

“You got it, Cap,” Rhodey told him. “We’ll hold down the fort here. You just worry about bringing our girl home safely.”

Ten minutes later, the small group stood in the Med Bay. Steve gently lifted his fiancée in his arms and adjusted her so her head was resting against his shoulder before turning to Natasha.

“Do it.”

The red-headed former assassin nodded and clicked the button on the extrapolator, causing a swirling grey and blue breech to open in front of them. Behind her, the newer people in the group were shocked.

“That is…different,” Pietro commented, his face seemingly in awe.

Rhodey sighed. “Just wait until you meet the ones on the other side.”

“You ready, Cap?” Tony looked at the man anxiously.

Steve felt the same way. “More than.”

“We’ll handle everything here,” Sam promised him.

Then, after making sure everyone was on the same page, the group of five walked through the breach and were gone.


	3. Looking for Barry

**Summary for the Chapter:**

> “But why would he come to this earth?” Iris questioned.
> 
> “Well, we believe…” Steve looked at Barry. “for you.”

_“I’m singing in the rain…”_

_“I told you.” Nora smiled at her young son as they watched the musical from their couch. “Everything’s better in song. When you speak, it’s just words. But when you sing, you open up your soul and let who you really are shine through.”_

_Barry smiled. “Thanks, Mom.”_

_Nora kissed his head and snuggled closer. “I love you, my beautiful boy.”_

_“I love you too.”_

Barry sighed as he watched “Singing in the Rain” and thought back to that moment with his mom from eighteen years ago. It was times like this when he was heartbroken and alone that he really missed her and wished she was still around to hold him like she had during his younger years.

He had really screwed up with Iris, he knew, and though they were barely on speaking terms, he desperately missed the love of his life. As he sat on Cisco’s couch, bundled up in a hoodie that he hoped would hide him from the world, he let himself drown in his sorrows.

Walking up behind him, Cisco shook his head. “This…again?”

The speedster sighed but didn’t respond.

“What, are you going to spend the rest of your life sitting around on the couch?” His friend asked him. “Come on.”

“No…” Barry groaned as Cisco tried to move him.

“You’ve been doing this for days.” The man told him. “Let’s do something. Let’s go out.”

“No, man, I’m sorry.” Barry shook his head again. “I…I don’t feel like going out.”

“What is it with you and musicals these days anyhow?”

“Everything’s better in song,” Barry informed him.

Cisco hesitated. “Listen, dude, I know you’ve been going through a tough time since Iris broke off the engagement, or I guess…”

“What?” Barry wondered sarcastically.

“…technically, since you broke off the engagement.” Cisco waved his hands in the air as if waving away the comment. “Whoever broke off the engagement, it doesn’t matter, I just…I don’t know, man. I want to help.”

“Nothing you can really do,” Barry said quietly.

“Really?” Cisco sighed. “I guess I’m just going to have to let Mr. Gene Kelly take over because, Lord knows, I can’t do anything about that.”

As he scoffed and Barry chuckled, their phones buzzed in unison. When they checked, Barry sat up and looked at his friend.

“It’s H.R.,” Cisco muttered.

Barry nodded. “Yeah…”

* * *

Arriving at S.T.A.R. Labs, Cisco and Barry hurried to the main work area, where they found H.R. and Wally standing in front of a large breach that had opened.

Without turning to face them, H.R. pointed at it. “B.A., someone’s coming through.”

“Could be Gypsy,” Cisco suggested, thinking of their friend.

H.R. nodded. “Could be. Or it could be…”

He trailed off at the breach started to make noise and pulse before closing and revealing Natasha, Tony, Layna, and Steve holding Kara’s body. Barry moved forward immediately at the sight of his unconscious friend.

“Supergirl…” H.R. whispered.

“Kara…” Barry looked at the group. “What happened to her?”

Tony shrugged. “We don’t know, but whoever did it came here, to this world.”

He felt panic rise up within him at the sight of them and wondered what could have happened that would take down his ridiculously powerful friend.

* * *

The group stood around the medical room as Caitlin checked Kara over, getting her own findings based on Helen’s report. As there were so many of them, they were slightly spread out around the room.

“Her vitals are low,” Catlin told them. “How long has she been like this?”

“A few hours,” Steve told her, his arms crossed over his chest.

Iris walked in the room as he spoke, having just arrived, and Natasha watched as Barry quietly nodded to her. She sensed that something was going on there but figured she could wait until later to find out what that was.

“Okay, we need to find whoever did this to Kara and punch him repeatedly until he reverses whatever spell he put on her,” Steve stated. “And I get to punch him first.”

“Who are you, exactly?” Cisco wondered.

“Steve Rogers. I’m-”

“Wait, you’re Captain America?” Everyone turned to look at Wally. “What? I read his comics growing up.”

Steve nodded. “Yeah, I’m Kara’s fiancé.”

“Not to totally change the subject,” Caitlin winced. “but I actually really only know Natasha…”

Barry sighed. “Guys, these are some of the Avengers. That’s Kara and Natasha’s superhero group back on their earth. Meet Steve Rogers and Tony Stark.”

“I can’t believe I’m meeting Tony Stark.” Cisco freaked out. “That is so awesome. I mean, I know this is a really bad time, but this is totally awesome.”

“Who’s the kid?” H.R. asked them, looking directly at Layna.

Embarrassed by the attention she was receiving, Layna blushed. “Hi.”

Seeing her embarrassment, Barry jumped in. “This is Layna. She’s Steve and Kara’s daughter.”

The preteen girl leaned in to hug him. “Hi, Uncle Barry.”

“Hey, honey.” He returned the hug and sighed. “How are you holding up?”

She just shrugged, and Tony turned to Steve. “I thought you guys were having issues. Why do you get to punch him first?”

“Hey, shh…” Steve glanced at Layna before leveling the engineer with a glare.

Thankfully, H.R. decided to speak up. “I tell you what; I know enough not to mention the break-up between Barry and…”

Iris shook her head. “H.R.”

He winced. “Sorry.”

‘Oh,’ Natasha thought to herself. ‘That sucks.’

She may come across uninterested sometimes, but she was sad for her friends and their breakup. She hoped they would find a way to work it out soon.

“Look, hey, whatever’s going on between me and Kara, I cannot leave her like this, okay?” Steve interrupted them in order to bring the focus back to their biggest dilemma. “I need to get her back.”

“We will,” Barry told him, then looked down at Layna. “I promise.”

“So, what happened to her?” Iris wondered, changing the subject.

“Some guy showed up in our compound during dinner and did something to her. He put her in some kind of coma, we’re guessing.” Natasha shrugged. “We have no idea where he came from or how he got in.”

“Then he disappeared. We tracked him here and followed.” Tony shook his head. “I am definitely upgrading FRIDAY’s security features when we get back.”

Barry’s brow furrowed. “FRIDAY? What happened to JARVIS?”

“It’s a…long story,” Nat muttered.

“But why would he come to this earth?” Iris questioned.

“Well, we believe…” Steve looked at Barry. “for you.”

“Me? Why?” The man was confused.

“We don’t know,” Nat said honestly. “But his last words before he disappeared were about finding the fastest man alive.”

“Yeah, and he obviously didn’t mean the Maximoff kid, or he’d have stayed on our earth,” Tony added.

At their confused looks, Nat shrugged again. “We’ve…added a few more members since we saw you guys last. We’ll fill you in later.”

“Noted.” Caitlin nodded, knowing to change the subject.

“Okay, well, clearly, we’re talking about a breacher here.” Cisco chimed in. “And if there’s one thing I can do, it’s find breachers.”

Looking at Barry, Layna frowned and followed them out of the room. “Am I supposed to know what that means?”


End file.
